1. Field of the Invention This invention relates to an electromechanical translation apparatus and more particularly to a piezoelectric electromechanical translation apparatus wherein clamping and translating elements selectively clamp a separate member in response to a variable clamping force produced from a plurality of piezoelectric driving elements to produce either linear or rotational relative movement between the electromechanical translation apparatus and a separate member.
2. Description of the Prior Art
The concept of a piezoelectric motor or an electromechanical device to produce rotational or linear relative movement between an electromechanical device and a driven member is known in the art.
A reversible motor with a piezoelectric rotor drive having a two-tier piezoelectric driving transducer which is driven by an oscillator and a phase sifter for high speed reverse operation is disclosed in Russian Patent No. SU-651-434. In this reversible motor, the two-tier transducer is arranged in a coplanar, stacked arrangement and has a common electrode in the adjacent opposed surfaces. The outer surface of each piezoelectric element has an electrode affixed thereto. An oscillator drives one piezoelectric element in contact with a shaft in a first direction and a second piezoelectric element, which is coupled to a housing and which supports the shaft for rotation, is driven by a phase shifter in a second direction producing relative movement between the shaft and housing which rotates the shaft. In this motor, the piezoelectric element directly clamps the exterior surface of the shaft.
A unidirectional piezoelectric motor having a wedge-shaped driving element which frictionally engages the exterior surface of a shaft to rotate the same in response to vibrations of a piezoelectric element coupled between the wedge-shaped driving element and housing which rotatably supports the shaft is disclosed in Russion Patent No. SU-635-538.
The use of a piezoelectric electromechanical translation apparatus using a multi-section, axially aligned piezoelectric driver to produce linear motion between the piezoelectric electromechanical translation apparatus and a shaft is disclosed in U.S. Pat. Nos. 3,902,084 and 3,902,085. In each of these apparatus, the piezoelectric driver directly engages and clamps the shaft through electrodes formed on the surface of piezoelectric crystal in order to produce incremental, stepped movement between the apparatus and the shaft.
A piezoelectric motor for producing angular motion which is capable of being transmitted to a remotely disposed rotatable element wherein polyphase electric potentials are applied to a plurality of piezoelectric crystal elements which are so arranged and interconnected that the vibratory movements thereof are translated into the rotational movement is disclosed in U.S. Pat. No. 2,439,499.
A dynamic balancing machine for detecting the periodic forces of unbalance of a rotary body and yielding a visual or other indication of the magnitude and orientation of such forces utilizing a means for supporting each end of a rotating body to be tested upon a pair of piezoelectric quartz crystal plates as the pickup elements which are arranged in a "V" shaped support is disclosed in U.S. Pat. No. 2,461,645.
Another piezoelectric driving device having an elongated piezoelectric driving bar which is resiliently mounted to drive an intermediate rotor in response to vibrations of the piezoelectric crystal and wherein the intermediate rotor drives a main rotor is disclosed in Russian Patent No. Su-636-760.
An electrical rotary apparatus utilizing four piezoelectric elements which are supported radially from and in an equally spaced relationship on a circular shaped housing and which are adapted to be expanded, in response to a magnetic field, to engage a shaft and wherein application of an AC signal to the piezoelectric element while in contact with the shaft causes relative movement between the housing and the shaft is disclosed in Russian Patent No. SU-688-033.